1. Field of the Invention
The present invention relates to a pressure instrument that has a control assembly placed into an explosion proof housing and easily coupled and uncoupled from components in the housing, including drive connections for rotary controls.
2. Description of the Prior Art
Various pressure instruments such as current-to-pressure converters and pressure transmitters have been advanced in the art, and some have modular construction. However, having a modular functional assembly that can be removed for cleaning, service or replacement without disrupting the set points of rotatable potentiometers such as for span or zeroing, has been a problem. Because these adjustments have to be accessible under an easily removable cover and the circuit components have to be in a flame-proof compartment or cavity in many installations, the adjustment drive components have to be accessible on the exterior of a wall forming the cavity while the circuit components driven by the adjustment drive components are on the interior of the cavity. End users desire units which are easily repaired. Yet if the circuit assembly is removed from the housing cavity to be cleaned or for minor repairs, reconnection of the drive and driven components has been difficult because of alignment differences.